nightmere castle

When nightmare castle enter the battlefield put x nightmare counters on nightmare castle and
discard x cards.
Nightmare creature you control get +1/+1
{t}add{b}{b}
{b}{b}{2}{t}put a x/x nightmare creature on the battlefield .x is the number of nightmare counters
{3}{ut}you gains 3 life each opponent can
active this abillity.